[6782] in Athena Bugs
termcap compatability
daemon@ATHENA.MIT.EDU (daemon@ATHENA.MIT.EDU)
Thu Jan 3 16:18:31 1991
Date: Thu, 3 Jan 91 16:18:17 -0500
From: Mark Rosenstein <mar@MIT.EDU>
To: bugs@MIT.EDU
Date: Thu, 13 Dec 90 18:02:09 EST
From: Jerome H Saltzer <Saltzer@MIT.EDU>
Sender: <Saltzer@MIT.EDU>
To: mar@MIT.EDU
Cc: jis@MIT.EDU
In-Reply-To: Mark Rosenstein's message of Thu, 6 Dec 90 18:16:31 -0500 <9012062316.AA12971@Toto.MIT.EDU>
Subject: Re: maintaining a mailing list
Repository: PTT
Originating-Client: NE43-513-2
> ...any member of the MIT community is eligible to get a kerberos
> principal in the ATHENA.MIT.EDU realm. All they have to do is run
> register by ... telnetting to athena.dialup.mit.edu and logging in as
> "register", password "athena". ...
Mark,
(cc to Jeff because he is the person who originally alerted me that
this facility was becoming available.)
My secretary just successfully completed this procedure, but one
medium-size glitch showed up. When she logged in, the dialup machine
responded with "TYPE X11TERM UNKNOWN" and proceeded to operate with
some vanilla terminal type. Needless to say, the interaction with the
menus did not go terribly well.
We tried again after doing a "set term=vt100" on her workstation and
all went smoothly.
What seems to have gone wrong is that her LCS workstation has the
latest telnet implementation, which tries to be helpful by passing
along the terminal type. The Athena dialup machines are running the
latest telnetd, which tries to be helpful by accepting the terminal
type and looking it up in termcap, rather than asking you what kind
you have.
The trouble is, this procedure falls into a hole unless both ends
agree on the exact name to be used for the terminal type. To deal
with this problem, RFC-1060 conveniently supplies a list of standard
names.
As far as I can tell, noone quite implements this list. According to
RFC-1060, my secretary's machine should have supplied the name
"xterm", which the Athena termcap recognizes. But her machine is
running X11R3, and I am told that all X11R3 xterms claim that their
type is "x11term". We are fixing her .login to set her term variable
to xterm, so she won't have the problem any more. But other people
are going to trip on this.
Neither end is actually up to par on standards. I have a shiny new
version of FTP software's PC/TCP, whose telnet offers its terminal
type as "DEC-VT220" (exactly as specified in RFC-1060).
Unfortunately, the standard Athena termcap doesn't know about this
terminal type. It knows about VT220 and vt200 and dec-vt200, but not
about DEC-VT220, the official name.
I recommend that the Athena termcap be reviewed in light of RFC-1060,
and make sure that the standard names are available as synonyms for
every supported terminal type. If it is too late to get this change
into the IAP release, it might even be worthwhile to temporarily
hand-install an updated termcap on the dial-in machines, where it
matters most.
As for logging in to Moira to take advantage of the Kerberos
registration features, people from outside Athena who have old
termcaps with a new login are going to run into the problem that my
secretary did. I don't know how hard the following is to do, but the
right solution would seem to be, if the terminal type supplied by the
telnet client is unknown, ask the traditional "TERMINAL TYPE? "
question and continue looping around that question until the user
supplies an acceptable terminal type. (This may be just a matter of
a slight modification of the .login for the moira and athena accounts.)
Jerry
